Check USCIS case status online If you have a receipt number for an application filed with USCIS, you can check your USCIS case status online. First you need to locate your receipt number. USCIS receipt numbers start with three letters. Those first three letters indicate which USCIS service center is processing your application. We will decipher those first three letters from USCIS receipt numbers immediately below. USCIS receipt numbers starting with: EAC – Eastern Adjudication Center,...